1. Field of the Invention
The present invention generally relates to a communication method, a communication system, and a communication apparatus and particularly to a communication method, a communication system, and a communication apparatus in a communication system having a base station for transmitting a beacon and a terminal for performing communication with the base station.
2. Description of the Related Art
In an electronic shelf label system, an electronic shelf label having rewritable display information is registered in a host computer and then attached to a product shelf. It is possible to rewrite the display information of the electronic shelf label from the host computer by accessing the electronic shelf label through an access point (refer to Patent Documents 1 to 5).
Such an electronic shelf label system employs a communication method such as IEEE 802.15.4 or the like, in which a beacon periodically transmitted by a coordinator is used as a standard and each node performs transmission and reception processing. In this communication method, when the coordinator is to transmit data to a certain node, an ID of the node is inserted into a beacon.
Each node that receives a beacon return a response when the ID included in the beacon corresponds to its own ID. When the ID included in the beacon does not correspond to its own ID, the node ends reception processing and enters a sleep mode.
Patent Document 1: Japanese Laid-Open Patent Application No. 2002-304673
Patent Document 2: Japanese Laid-Open Patent Application No. 2005-99888
Patent Document 3: Japanese Laid-Open Patent Application No. 2002-109177
Patent Document 4: Japanese Laid-Open Patent Application No. 2004-265196
Patent Document 5: Japanese Laid-Open Patent Application No. 9-138892
In a conventional communication method, in proportion as a period of time from beacon reception to sleep mode based on a judgment that the received beacon is not addressed to the node is reduced, lower power consumption is realized. However, when the number of nodes is increased and the number of bits of ID is increased, this poses problems in that power consumption is increased, for example.